Establishment of Reference Intervals of Serum Immunoglobulins in Healthy Korean Adults

Abstract

It is known that humoral immunological disease (excess or deficiency) is caused by quantitative/ functional deficiency in or excess of total immunoglobulins (e.g., immunoglobulin (Ig) G, A and M) and/or IgG subclasses (IgGSCs). Although the prevalence of this disease is low in adults, IgG3 subclass deficiency (IGG3SCD) has been found to be associated with asthma exacerbation in adult asthmatic patients, and IgG4-related disease has been reported in patients with asthma.1,2 Considering that age, sex and ethnicity could affect IgG and IgGSC concentrations, it is essential to establish proper cutoffs each of Ig and IgGSC levels in our population.3 To evaluate IgGSC concentration, turbidimetric immunoassay (TIA) and nephelometry (Nep) have been widely used in practice in which Nep is thought to be more sensitive but expensive than TIA. The present study aimed to determine the reference interval (RI) each of Igs and IgGSCs in Korean adults for the diagnosis and monitoring of patients with humoral immunologic disease including IgG3SCD-or IgG4-related disease. This study was approved by the Ajou University Institutional Review Board, and all informed consent forms were obtained from all participants (AJIRB-Med-SMP-18-207).